Reverse Print On Reverse!

I just found a stamp which appears to have been printed on both sides. However, one of the prints is reversed. Is this what's called an offset? How is this even possible? I'm puzzled.

The proper name is setoff.

I used Photoshop to generate the image above. Note that the 'printed on reverse' stamp would show the design in the correct orientation (just like the front side of the stamp) while an 'setoff' stamp has the design mirrored or reverse.

'Setoff' occurs when the sheets picked up the freshly printed, wet ink while being stacked.
Don

Thanks for the information. In this case, the reverse print looks identical to the print on the other side, except for being reversed. In other words, it shows the complete design. It's very strange!

For me, this is also interesting and not to explain with the normal setoff. I also have such a stamp I showed here:
https://goscf.com/t/53636

And here at SCF I found another thread with this explanation:
OFFSET: (Print appearing on the gummed side of stamps). Imagine, with reference to the gravure diagram above, if there is no paper between the cylinders. The ink/image is then transferred to the impression cylinder. Next time paper passes through this is transferred from the impression cylinder onto the reverse side of the paper, in mirror image/reversed, gradually fading away with each revolution. THIS IS NOT SETOFF.
SETOFF: This is where the finished sheets coming off the printing press, are still wet. When stacked some of this wet ink smudges onto to reverse of the sheet above. Printers sometimes spray a fine white powder on to the sheets as they come off the press. This is to try and prevent this setoff happening. That's why some printing presses have the appearance of being snow covered. Gravure presses do not suffer with this problem very often, the solvents used make the ink dry very fast. Modern presses have UV/INFRA RED driers to help dry the ink faster, avoiding this problem.

Sadly there, nowhere else on SCF and the internet I found similar explanations which appear logical to me. So there has to be a difference between normal setoff and this kind of "other printing error", which could be calld offset, or perhaps "half offset". Any experts to confirm this? For me a setoff would not be so detailed like the one shown above. But I am not an expert.

Most interesting stamperix!

This is the stamp in question, which I finally got around to scanning:



This was found in an old album, so suffers from hinge staining.

If the paper is thin and/or porous, the impression with its ink from one side (front) can pass through the paper onto the other side (back) as an ink bleed through the paper. If the front image is located in the exact same position as the back image, then it is most likely this.

jogil, that's what I thought at first - the problem is that the paper is actually quite thick.

I did some research today and learned that these stamps sometimes had post office advertisements printed on the back. It's possible the error arose as a result of deliberately printing on the reverse.

jimjamtwo: Do you know if it is porous rice paper? See: http://www.rice-paper.com/about/about.html

hello jimjamtwo,

your stamp is interesting, and you could easily check the pass-through if you hold the stamp against the light. Actually at the beginning I thought that the stamp Don showed were your one. My stamp is similar to Don's. For both cases, I still wonder why there isn't this differene between setoff and "half offset" in any glossary or stamp book explained. Also, in my opinion the "half offset" would be very fine fitting to the definition of "printed on the back", as it's not a setoff by wet ink, but some error in the printing process.

As far as I know a 'printed on back' error will always appear in the correct orientation, not a reversed (or mirrored) image.
Don

Yes, but what about the (good) explanation someone gave here on SCF and which I wrote above? ("offset") Even me, without being printing expert, can follow it. And it is reversed, and some "printed on back", both.

by the way this was the original thread there: https://goscf.com/t/26376#226039
but in this old thread, nobody really answered to it but all the people just made a terminological discussion out of it.
(the definition seem to be from http://stamphelp.com )

perhaps I will make another scan of my stamp and will show it later or soon. ----ok I made it now :).

Here the image. I think there is setoff, but additionall there is the whole image in a good quality.




PS: Sorry jimjamtwo for asking about my own stamp, but as mentioned I thought at the beginning that it's just this what is on your stamp as well. Your stamp is quite different, but if you check if it's pass through, you could at the end be as happy as me if someone has an answer to the setoff / offset question.

Setoff is when ink has been transferred to the back of a stamp in some way other than being fed back into the printer. This might be a few ink spots, a partial design, or even a complete design.

A true 'printed on back' stamps comes from a sheet was accidently fed back in the press upside down. If the sheet is fed back into the press upside down then the image is not reversed, the design will appear exactly like the front of a stamp.

'Printed on back' errors are rare, setoffs are common.

jimjam's stamp seems unusually sharp and complete, I assume that this is why jogil is asking about paper thickness. The easy way to determine if it is simply bleed through is to do as he suggested; hold it to a light and see if the design from the front side lines up with the revered image on the back.
Don

P.S. - there seems to be some confusion with the nomenclature. 'Setoff' is the term used by many printers and trades people. Stamp hobbyists use both the term setoff and offset to describe the same thing. But this is confusing since offset is also the term used for a specific type of printing (i.e., flat plate, rotary, or offset). As such, I think it is best to stick to the term setoff when describing a stamp when ink has transferred to the back of a stamp. Others may disagree.

Hello Don,

thank you for the explanation. Yes, I know that my stamp (and your image) is not a "real" printed on back. But it's not a classic setoff either. So what about the explanation about "offset" I found? (please don't focus on the name, it's really not about the name offset va. setoff here, but if there are two different "printing phenomenons" happening, which I suppose.) Also, I think I have setoff AND "offset" on my stamp, as shown.

As far as I can tell, the reverse image is in the exact same location as the image on the front, which is why it seems like it's a case of the ink bleeding right through the paper.

However, the paper is thick and the colour on the reverse is pretty much the same (i.e. equally intense) as on the front. When you view with the naked eye, it really looks like it is printed on both sides.

The normal paper for this stamp was apparently watermarked Manchukuo paper. It's soft, fairly thin and the watermark can easily be seen. By contrast, this paper seems hard and unwatermarked. It has a sort of 'starchy' feel so possibly is rice paper, if thick rice paper exists. It is not transparent.

Don your computer skills are really something, good on you.

My avatar is, if remember correctly 2.5mm and to get the right definition or this error for this stamp is 3mm.

This avatar is the closet stamp to this type of error I have ever had.

Interesting how the images look like the stamp is soaking wet and you get that type of look. I know they are not and no slur to anyone.